1. Field of the Invention
The present invention relates generally to the fabrication of structures on semiconductor wafers, and more specifically to apparatus used to condition preparation surfaces in chemical mechanical planarization process equipment.
2. Description of the Related Art
In the fabrication of semiconductor devices, integrated circuits are defined on semiconductor wafers by forming a plurality of layers over one another resulting in multi-level structures. As a result of the various layers disposed over one another, a surface topography of the wafer can become irregular, and an un-corrected irregularity increases with subsequent layers. Chemical Mechanical Planarization (CMP) has developed as a fabrication process utilized to planarize the surface of a semiconductor wafer, as well as to perform additional fabrication processes including polishing, buffing, substrate cleaning, etching processes, and the like.
In general, CMP processes involve the holding and rotating of a wafer against a processing surface under a controlled pressure. Typical CMP apparatus include linear belt processing systems in which a belt having a processing surface is supported between two or more drums or rollers which move the belt through a rotary path presenting a flat processing surface against which the wafer is applied. Typically, the wafer is supported and rotated by a wafer carrier, and a polishing platen is configured on the underside of the belt traveling in its circular path. The platen provides a stable surface over which the belt travels, and the wafer is applied to the processing surface of the belt against the stable surface provided by the platen.
Additional CMP apparatus include rotary CMP processing tools having a circular pad configuration for the processing surface, an orbital CMP processing tool similar to the circular CMP processing tool, a sub-aperture CMP processing tool, and other CMP processing systems providing a plurality of apparatus and configurations that, in general, utilize friction to planarize, polish, buff, clean, or otherwise process the surface of a semiconductor wafer having integrated circuits or other structures fabricated thereon.
CMP processing can include the use of varying degrees of abrasives, chemistries, fluids, and the like to maximize effective use of friction for wafer surface preparation, and several apparatus include providing for in-situ rinsing of wafers to reduce or remove the residue of CMP processing, as well as providing for cleaning and conditioning of processing surfaces during processing to increase processing surface life, and to maintain controllable and steady state processing.
In some CMP process systems, conditioning pads are used to condition or roughen the processing surface. Typically, conditioning pads are configured in pucks and mounted in a positioning arm that applies the conditioning puck against the processing surface to roughen, or rough up, the processing surface, and dislodge slurry and processing residue. The processing surface is typically a finely porous surface which can become saturated and bogged down with slurry and CMP process residue. After conditioning with the conditioning puck, additional rinsing is then implemented in some CMP processing tools to remove the dislodged slurry and other processing residue from the processing surface.
Prior art conditioning methods include sweeping the conditioning puck across the processing surface to achieve conditioning of the entire processing surface. Conditioning pucks are applied against the processing surface with sufficient downward (e.g., into the processing surface) force to condition into the texture of the processing surface. Additionally, a lateral force is applied to the conditioning puck when it is swept across the processing surface, and additional lateral forces are applied to the conditioning puck from the motion of the processing surface. Examples of processing surface forces include linear travel in linear belt processing systems, and rotary motion of rotary CMP processing tools. The combination of forces to which conditioning pucks are subjected contribute to significant and rapid wear of conditioning pucks, and necessary down-time of CMP processing systems for conditioning puck replacement.
What is needed are methods, processes, and apparatus to maximize the effective service life, and the effective implementation of conditioning pucks. The methods, processes, and apparatus should be easy to manufacture, and easy to implement in both currently operating and future CMP processing systems.